This invention relates to the field of paints generally and, more particularly, to non-toxic paints in either a liquid or semi-liquid form, and methods for their manufacture. Even more particularly, the present invention relates to a liquid non-toxic paint having a substantial wet-shelf-life and methods for making same.
Typically, conventional paints have three main components: a binder, a filler and a pigment. Generally, the binder is a synthetic petroleum-based polymer resin with extremely long and complex molecules. During the time when some normal synthetic resin polymerize, solvents, bactericides and surfactants, materials that may be hazardous to human health, are released into the atmosphere. The presence of such materials in the atmosphere has been linked to serious pathological conditions, including tumors, cancer, acute allergies, asthma, bone disorders, and the like. In fact, these diseases may be considered commonplace in the paint industry despite their assured undesirability. Additionally, once formed, it is believed that the paint film may deteriorate over time and produce dusts that may also pose serious health hazards when inhaled. Also, the filler and pigment components may contain substances possibly known to be hazardous to the environment and human health.
Even water-based paints containing acrylic resins, often portrayed in advertising as xe2x80x9cnon-toxic,xe2x80x9d are made with solvents, bactericides and other harmful components that may be released into the atmosphere, especially before polymerization occurs. Such components may be insidious and extremely dangerous, despite the fact that they are virtually odorless. Consequently, there is a need for a non-toxic paint that does not contain these undesirable components and does not present problems for humans or the environment.
One form of heretofore known non-toxic paint is referred to as milk paint and is of ancient origins. Milk paint typically utilizes milk protein, known as casein, as a binder rather than a synthetic or petroleum-based binder. Lime and pigments such as earth oxides are typically mixed with the milk protein to form a non-toxic powdered milk paint. These powdered paint compositions can then be mixed with water by the consumer to form a liquid (albeit very grainy) paint possibly suitable for use in a variety of applications.
Requiring the consumer (who is not likely familiar with making homogeneous paint compositions) to be responsible for mixing the powdered milk paint with water is extremely problematic. For example, substantial foaming occurs when the powdered paint is mixed with water. The foaming must be controlled to achieve a suitably homogenous mixture; a feat not easily accomplished by the ordinary consumer. Further, if adequate mixing is not obtained, the resulting shades and textures are usually not repeatable, resulting in the ultimate dissatisfaction of the consumer, especially in situations where the consumer wishes to redecorate over surfaces where milk paints have been applied previously. This problem is exasperated by the fact that powdered milk paints do not offer one-coat coverage because of the rapid deterioration in the viscosity of the paint after mixing, and therefore, many batches of the paint must be mixed to finish even the smallest jobs. Other problems associated with these powdered milk paints are that they are considered a caustic material, and the powders themselves present dusting/inhalation hazards.
Despite their initial environmental attractiveness, another particularly salient drawback associated with milk-based paints is that after mixing with water they have a short wet-shelf-life; typically, three days or less. Some formulas of milk paint may last as long as two to four weeks, but their quality deteriorates over this time, and they become completely unsatisfactory to consumers within a few days after mixing. Thus, in reality, the paint must be discarded within a few days of mixing or opening if not used entirely. Alternatives, such as refrigeration, are unsatisfactory. Thus, it would be desirable if a premixed, non-toxic milk-based paint were available that has a substantially long wet-shelf-life. Furthermore, the quality of such paints should not deteriorate over the long shelf-life. Also, oftentimes, these paints have an undesirable sour-milk scent.
Therefore, there is an unaddressed and long-felt need for non-toxic paints (i.e., paints that contain little or preferably no harmful or hazardous materials, such as materials known to be carcinogens or mutagens). Further, there is a need for such paints to be readily available in a premixed liquid or semi-liquid form so that the paints can be immediately and easily used by consumers. Moreover, such liquid and semi-liquid non-toxic paints should be of the quality that would enable a consumer to obtain a uniform and appealing appearance and texture when using the paints. Additionally, it would be desirable if such paints had a pleasant smell.
Accordingly, the present invention provides for the manufacture of non-toxic paints that contain little or preferably no hazardous substances such as carcinogens or mutagens typically contained in or released by conventional paints. The present invention also provides non-toxic paints that have a substantially long wet-shelf-life, a stable consistency over time, and that can be purchased easily by consumers in liquid or semi-liquid form similar to conventional liquid paints. The non-toxic paints of the present invention also have the proper rheology, allowing for good brushability and one-coat application possibilities. Consequently, the present invention provides stable liquid or semi-liquid non-toxic paints that cannot only be stored for substantially long periods of time without spoiling, but also will be suitable for successive uses to obtain maximum effectiveness in covering power, texture, adhesion and aging in the finished job.
One feature of the non-toxic paints of the present invention is that the paint has excellent application and texturing qualities, covers well, and adheres to practically all surfaces, with the exception of some metal surfaces.
Another feature of the non-toxic paints of the present invention is that they have a lower pH, and therefore, do not present profound eye or skin irritation hazards as do conventional powdered-milk paints.
One embodiment of the non-toxic paints of the present invention comprises a vehicle (one embodiment of the vehicle comprising potassium sorbate and casein protein); a kaolin slurry; and a pigment dispersion.
One embodiment of a method of manufacturing the non-toxic paint compositions of the present invention includes the steps of: providing a vehicle; providing a kaolin slurry; providing a pigment dispersion; and mixing the vehicle, the kaolin slurry, and the pigment dispersion so as to form a liquid or semi-liquid non-toxic paint.
Other and further objects, features and advantages will be apparent from the following description of some embodiments of the invention.